GIS Library - Getting ellipsoid parameters from the database. More...

#include <unistd.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <grass/gis.h>
#include <grass/glocale.h>

Include dependency graph for get_ellipse.c:

Go to the source code of this file.

Functions
int	G_get_ellipsoid_parameters (double a, double e2)
	get ellipsoid parameters

int	G_get_ellipsoid_by_name (const char name, double a, double *e2)
	Get ellipsoid parameters by name.

const char *	G_ellipsoid_name (int n)
	Get ellipsoid name.

int	G_get_spheroid_by_name (const char name, double a, double e2, double f)
	Get spheroid parameters by name.

const char *	G_ellipsoid_description (int n)
	Get description for nth ellipsoid.

int	G_read_ellipsoid_table (int fatal)
	Read ellipsoid table.

Detailed Description

GIS Library - Getting ellipsoid parameters from the database.

This routine returns the ellipsoid parameters from the database. If the PROJECTION_FILE exists in the PERMANENT mapset, read info from that file, otherwise return WGS 84 values.

New 05/2000 by al: for datum shift the f parameter is needed too. This all is not a clean design, but it keeps backward- compatibility. Looks up ellipsoid in ellipsoid table and returns the a, e2 and f parameters for the ellipsoid

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author: CERL

Definition in file get_ellipse.c.

Function Documentation

◆ G_ellipsoid_description()

const char * G_ellipsoid_description ( int n )

Get description for nth ellipsoid.

This function returns a pointer to the description text for the nth ellipsoid. If n is less than 0 or greater than the number of known ellipsoids, it returns a NULL pointer.

Parameters

n	ellipsoid identificator

Returns: pointer to ellipsoid description; NULL if no ellipsoid found

Definition at line 182 of file get_ellipse.c.

References G_read_ellipsoid_table(), and NULL.

◆ G_ellipsoid_name()

const char * G_ellipsoid_name ( int n )

Get ellipsoid name.

This function returns a pointer to the short name for the nth ellipsoid. If n is less than 0 or greater than the number of known ellipsoids, it returns a NULL pointer.

Parameters

n	ellipsoid identificator

Returns: ellipsoid name; NULL if no ellipsoid found

Definition at line 132 of file get_ellipse.c.

References G_read_ellipsoid_table(), AMI_STREAM< T >::name(), and NULL.

◆ G_get_ellipsoid_by_name()

int G_get_ellipsoid_by_name	(	const char *	name,
		double *	a,
		double *	e2
	)

Get ellipsoid parameters by name.

This routine returns the semi-major axis a (in meters) and eccentricity squared e2 for the named ellipsoid.

Parameters

	name	ellipsoid name
[out]	a	semi-major axis
[out]	e2	eccentricity squared

Returns: 1 on success; 0 if ellipsoid not found

Definition at line 104 of file get_ellipse.c.

References G_read_ellipsoid_table(), G_strcasecmp(), AMI_STREAM< T >::name(), and name.

Referenced by G_compare_projections().

◆ G_get_ellipsoid_parameters()

int G_get_ellipsoid_parameters	(	double *	a,
		double *	e2
	)

get ellipsoid parameters

This routine returns the semi-major axis a (in meters) and the eccentricity squared e2 for the ellipsoid associated with the database. If there is no ellipsoid explicitly associated with the database, it returns the values for the WGS 84 ellipsoid.

Parameters